Power transmission



5 Sheets-Sheet INVENTOR ATTORNEY Oct. 8, 1940. E. L. ROSE,

POWER TRANSMISSION Filed Nov. 17, 1956 Enw/r/ L. ROSE 'Oct. 8, 1940. E. L. ROSE POWER TRANSMISSION Filed Nov. 17, 1936 3 Sheets-Sheet 3 INVENTOR\ Elnwuv Digs M M ATTORNEY Patented Oct. 8, 1940 POWER TRANSMISSION Edwin L. Rose, Watertown, Coma, assignor to The -Waterbury Tool Company, Waterbury, onn., a corporation of Connecticut Application November 17, 1936, Serial No. 111,241

. v 6 Claims.

This invention relates to power transmissions, particularly to those of the type comprising one or more fluid pressure energy translating devices, one of which may function as a pump and another as a fiuid motor. The invention is particularly 7 concerned with, a method of manufacturing a subassembly for a fluid pressure energy translating device of the rotary barrel and swash plate type, such a-sub-assembly including a bail ended connecting rod having a one-piece piston mounted on one ball end and a one-piece socket member mounted on the other ball end.

In devices of this character as heretofore constructed the ball and socket joints at the piston and at the socket ring have usually been formed with a split socket member which is assembled together to embrace the ball by suitable screw 0 process requiring a large amount of skilled hand labor. Inasmuch as a complete power transmission ordinarily utilizes .irom twenty-eight to thirty-six such ball and socket joints, the labor involved in hand fitting is a substantiaLpart of the cost of the transmission. While it has long been known that it would be desirable to form such ball and socket joints by deforming a one-piece socket member to embrace a ball, heretofore no satisfactory method for doing this has been evolved. Inasmuch as it is absolutely necessary to provide an exact and a uniform clearance between the ball and the socket to provide for film lubrication and to prevent lost motion, previous attempts in this direction have been unsatisfactory since it has been impossible to control such clearance precisely. v

It is an object of the present invention to pro,- vide a novel method and apparatus for forming a one-piece socket member embracing a ball M9 member over more than a hemisphere, to form a ball joint with uniform clearance and without lost motion when properly lubricated.

A further object is to provide a method of formw ing a sub-assembly unit comprising a piston, a connecting rod, and a socket member articulated together by integral ball joint constructions.

Further objects and advantages of the present invention will be apparent from the following de- 50 scription, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In .he drawings: Fig. 1 is a longitudinal cross section of a drawuli ing apparatus showing a piston and connecting the cylindrical outer surface of a piston.

Fig. 4 is a cross section on line 4-4 of Fig. 3.

Fig. 5 is a view showing a lathe operation performed after the sizing operation of Fig. 3.

Fig. 6 is a diagrammatic 'cross section of a 10 swaging press showing a piston, connecting rod, and socket member assembled therein prior to swaging.

Fig. 7 is a view corresponding to Fig. 6 after the swaging operation has been completed. 16

Fig. 8 is a longitudinal sectional view of a completed piston, connecting rod and socket member sub-assembly.

Fig. 9 is a longitudinal cross section of a drawing press for performing a modification oi the 20 -method of the present invention and illustrating a piston, connecting rod and socket member assembly. prior to the drawing operation.

Fig. 10 is a view corresponding to Fig. 9 after the completion of the drawing operation. 25

Fig. 11 is a longitudinal section of a modified form or a sub-assembly made in accordance with Figs. 9 and 10.

Fig. 12 is a cross section on line l2 -i2 of Fig.9. i

' According to the form of the invention illustrated in Figs. 1 through 8, a connecting rod ill is formed having a small ball end i2 and a large ball end II. The connecting rod may be formed of hardened steel with the ball ends I! and i4 accurately ground to true spherical shape except for balancing, and lubricating grooves it formed on the ball II. A piston member ID is formed with a cylindrical bore 20 open at one end and terminating at the opposite end in a hemispherical socket 22, a suitablelubricating groove 24 and bore 28 being provided. The outer surface of the piston I8 is formed as a cylinder interrupted by a raised annular band as indicated at 28. The diameter of the cylindrical outer surface is preferably somewhat larger than the desired finished diameter of the piston. The shape and size of the raised band 28 are held to precise limits which areinitially determined by experimentation and which, when once determined, may be readily duplicated by the use of aformed tool for turning the same.

The head end of the piston is provided with a cylindrical extension 30 having 'a conical center seat 32-ior a purpose later to be described. The 5 piston I8 is provided with a central lubricating bore 34 which communicates with a central bore, not shown, running the full length of the connecting rod I8. The piston is made of a ductile metal, it being preferred to use a beryllium-copper alloy which may be hardened by heat treatment. The piston and connecting rod are assembled with the ball I2 engaging the hemispherical seat 22. A split sleeve 36 is assembled to the connecting rod adjacent the piston end and is provided with a cylindrical shoulder 38 fitting the bore 28 having'a conical portion 48 extending to the ball I2. A'second split sleeve 42 is assembled to the connecting rod I8 adjacent the ball end H. The sleeves 36 and 42 are provided with reduced cylindrical portions 44 and 46 at their adjacent ends, in which is mounted and retained' by friction a split sleeve 48 which is as.

sembled with its plane of split out of register with those of the sleeves 36 and 42 (see Fig. 4).

The assembly comprising connecting rod I8, piston I8, sleeves 36, 42 and 48 is inserted endwise in a drawing die block 58 which is provided with a tapered bore 52 leading to a cylindrical bore 54, beyond which is an enlarged clearance bore 56. Extending into the bore 56 is a springloaded bell crank 58 pivoted at 68. A spring 62 and a ball 64 coact with a cam surface 66 on the bell crank 58 to urge the latter clockwise in Fig. 1 and thus hold the ball I2 snugly against the seat 22. A recess 68 is provided adjacent the cam surface 66 whereby the ball 64 may retain the bell crank 58 in the position illustrated in Fig. 2.

The drawing die block 50 carries removably secured thereto a guide cap I0 for guiding the piston I8 at the beginning of the drawing operation. A punch member I2 has a bore I4 for receiving the projection 38 and at its right-hand end abuts the head of the piston I8. The punch :12 and die block 58 may be assembled into any suitable press device whereby the punch I2 may be forced to the right in Fig. 1 to force the piston I8 and assembled parts through the tapered bore 52 and the cylindrical bore 54 of the die block 58.

The position and shape of the parts after such a drawing operation are illustrated in Fig. 2, from which it will be seen that the raised band 28 is forced radially inward to form a socket embracing the ball I2 over more than a hemisphere. The

cylindrical shoulder 38 on the sleeve 36 and the conical portion 48 serve to assist in localizing the deformation of the raised band-28 to insure accurate formation of the'socket.

At the completion of the drawing operation illustrated in Fig. 2;, the'assembly, including the sleeves 36, 42 and 48 is placed in a grinding machine, as illustrated in Fig. 3, with centers I6 engaging the center seat 32 and a similar seat, not shown in the ball I4. The outer surface of the piston I8 is ground down to the precise finished diameter required by a grinding wheel I8. If desired, the grinding may be performed in a centerless grinding machine in which case the extension 38 may be omitted from the piston I8 when first formed.

After the grinding operation the assembly may be chucked in a lathe and the extension 38 cut off by a cut-off tool 88 as illustrated in Fig. 5. The piston may then be heat treated to increase its hardness. The connecting rod I0 with the finished piston I8 assembled thereon is next detached from the sleeves 36, 42 and 48, and assembled to a socket member 82 having a cylindrical bore 84 terminating in a hemispherical seat 86. The assembly is inserted in a die block 81 having a bore 88 receiving the piston I8 and having a partially spherical socket 98 at the right-hand end of the bore 88. A spring 92 urges the piston I8 to the right and maintains the ball I4 in contact with the seat 86. The die block 81 may be assembled in a hydraulic press which is indicated diagrammatically as having a movable platen 84 operated by a hydraulic piston 96. .The piston 96 operates in a cylinder 98 to which fluid is supplied bya reversible, variable delivery pump I08. The pressure which can be exerted by the platen 94 is limited by an adjustable pressure relief valve I82 connected across the pump I88, a manual bypass valve I84 being also provided for controlling the operation of the press.

With the parts assembled as illustrated in Fig. 6, the by-pass valve I 84. may be closed and the pump controlled to deliver fluid into the righthand end of the cylinder 98. The socket member 82 is thus forced into the spherical socket 98, deforming the cylindrical bore 84 radially inward to form an integral socket embracing the ball I4 over more than a hemisphere, as illustrated in Fig. 7.. The use of a hydraulic press with controlled maximum pressure enables the clearance between the ball I4 and the finished socket to be precisely controlled independently of variations in the axial distance between the center of the hemispherical seat 86 and the end face of the socket member 82. The press platen is opened and the completed assembly may be removed I from the die block 81 with a finished appearance similar to the raised band 28 on the piston I8.

Split sleeves H2 and H6 are assembled to the connecting rod I0 and retained in position frictionally by a third split sleeve I'I8. This assembly is then positioned on a stationary abutment I28 and a manually adjustable abutment I22 which may be moved toward and away from the abutment I28 by a screw I24 and a hand wheel I26. The abutments I20 and I 22 are preferably provided with conical centers I28 and I30 receiv-,

able in corresponding depressions in the piston I86 and the socket member I88 respectively. A 0

pair of movable drawing dies I82 and I34 surround the abutments I28 and I22 respectively and are provided with conical bores I36 and I38 terminating in cylindrical bores I48 and I42, respectively.

The die blocks I32 and I34 are then moved toward each other into the position illustrated in Fig. 10, thus forcing the raised bands H0 and 28 radially inward to form sockets embracing the balls I2 and I4 in a manner similar to that illustrated in Figs. 1 and 2. The diameter of the cylindrical outer portion of the piston I86 before drawing is slightly greater than the desired finished diameter of the piston I86, the finishing being done, however, by the drawing operation rather than by an additional grinding operation. Thus the material on either side of the raised band 28 is compacted radially inward to the diameter of the cylindrical portion I42, providing a precisely controlled and uniform piston diameter as well as providing a smooth exterior finish. The completed sub-assembly after removal of the split sleeves H2, H6 and H8 is illustrated in Fig. 11.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form. it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1 The method of forming a piston and con necting rod assembly which comprises forming a connecting rod with a ball end, forming a piston with a cylindrical bore terminating in a concave hemispherical surface to match the ball end. of

the connecting rod and with a cylindrical outer surface interrupted by a raised band axially spaced from the open end of the bore, deforming said raised band radially inward while maintaining the ball end in contact with said hemispherical surface and while supporting the outer portion of said cylindrical bore against deformation to form a socket embracing the ball end over more than a hemisphere, and reducing the outer surface of the piston to a predetermined diameter..

2. The method of forming a piston and connecting rod assembly which comprises forming from the connecting rod the outer portion of said cylindrical bore against deformation to form a socket embracing the ball end over more than a hemisphere, and reducing the outer surface of the piston to a predetermined diameter.

3. The method of forming a piston and connecting rod assembly which comprisesforming a connecting rod with a ball end, forming a piston with a cylindrical bore terminating in a concave hemispherical surface to match the ball end of the connecting rod and with a cylindrical outer surface interrupted by a raised band axially spaced from the open end of the bore, deforming said raised ba'nd radially inward while maintaining the ball end in contact with said hemispherical surface and while supporting the outer portion of said cylindrical bore against deformation to form a socket embracing the -ball. end over more than a hemisphere, and simultaneously drawing down the outer surface of the piston to a predetermined diameter.

4. The method of forming a piston, connecting rod and ball joint assembly which comprises forming a connecting rod with ball'ends, forming a piston with a cylindrical bore terminating in a concave hemispherical surface to match a ball end of the connecting rod and with a cylindrical outer surface interrupted by a raised band, forming a socket member with a cylindrical bore terminating in a concave hemispherical surface to match the other ball end and with a cylindrical outer surface interrupted by a raised band, concomitantly deforming said raised bands, radially inward while maintaining the ball ends in contact with their respective hemispherical surfaces to form sockets embracing the ball ends over more than a hemisphere, and simultaneously drawing down the outer surface of the piston to a predetermined diameter.

5. The method of forming a ball and socket joint having a one-piece socket which comprises forming a socket member with a cylindrical bore terminating in a concave hemispherical surface and with a cylindrical outer surface having a raised band axially spaced from the open end of the bore, and deforming the raised band radially inward while maintaining a ball in contact with the hemispherical surface and while supporting the outer portion of said ,cylindrical bore against deformation to form a socket embracing the ball over more than a hemisphere.

6. The method of forming a ball and socket joint having a one-piece socket which comprises forming a socket member with a cylindrical bore terminating in a concave hemispherical surface and with a cylindrical outer surface having a raised band axially spaced from the open end of the bore, and deforming the raised band radially inward by a drawing operation while maintaining a ball in contact with the hemispherical surface and while supporting the outer portion of said cylindrical bore against deformation to form a socket embracing the ball over more than a hemisphere.

EDWIN L. ROSE. 

